In some buffering systems, two or more buffers may each be selectively designated for purposes of displaying onto a display screen. For example, one buffer may be designated as the front buffer which is actively being displayed by the display screen. The other buffer may be designated as the back buffer which is being drawn or rendered while the front buffer is being displayed. When a suitable trigger occurs such as drawing completion of the back buffer, or after a predetermined refresh interval, the roles of the two buffers may be switched or swapped, for example by modifying a pointer or address to the other buffer. In this instance, the original back buffer is now the front buffer and the original front buffer is now the back buffer. The new back buffer is now designated for rendering or drawing of a next graphic. This process may sometimes be referred to as buffer swapping, page flipping, ping-pong buffering, or generally as double buffering.
Another feature of some buffer swapping systems is to provide a copy-back or preserve function. In such a function, upon swapping, the new front buffer is automatically copied to the new back buffer. A difficulty with some buffer swapping systems is that each instance of buffer copying typically requires a full screen of pixels to be copied from one buffer to another buffer, which can require processor time commitments and may be wasteful on processor resources.
Other difficulties with existing systems may be appreciated in view of the detailed description herein below.
Like reference numerals are used throughout the Figures to denote similar elements and features.